This application claims the priority of German patent document 198 41 751, filed Sep. 11, 1998 and PCT International Application No. PCT/EP99/06065, filed Aug. 19 1999, the disclosures of which are expressly incorporated by reference herein.
The invention relates to a device for adjusting the height positioning of the body of a vehicle.
As a rule, vehicles are nowadays constructed to offer the highest possible passive safety in the event of collisions. For this purpose, measures have been implemented in all parts of the vehicle to strengthen it and to absorb the highest possible kinetic energy in the event of a collision.
However, as a result of differences in size and height, vehicles often experience an underride or impact of foreign objects or other vehicles onto a portion of the vehicle structure which is less reinforced than other parts. For example, in a frontal collision with a truck, a passenger car front hood will impact on the truck bumper. Also when driving into parking spaces, the levels of bumpers often do not match. During side collisions, impact usually occurs not in the particularly stable side member region, but in a region situated above it.
Japanese Patent Document JP-A-04046814 discloses a level adjusting device for a vehicle which is intended to reduce a risk of injury to pedestrians in the event of a collision. For this purpose, a detection device detects whether a collision with a pedestrian is imminent. If so, the level of the vehicle is lowered on the collision side or on the front side in order to reduce the power of the impact. However, this system is not suitable for increasing passive safety in a motor vehicle that collides with another hard object.
One object of the invention is to provide a level control system by which, in the event of a collision, assures that the impact occurs on a well reinforced region of the vehicle.
This and other objects and advantages are achieved by the vehicle elevation control system according to the invention, in which a detection device generates data of an object approaching the vehicle. These data may be, for example, the relative speed, the distance or the contour of an approaching object. The detection device can also evaluate data from a Global Positioning System (GPS), telemetry data or other external data for determining the relative approaching of another vehicle.
A processing device is constructed such that it can reliably determine an imminent collision from the data supplied by the detection device. For this purpose, an algorithm must be selected which, if possible, avoids a faulty triggering. It is advantageous, for example, to carry out the securing measure of a corresponding vehicle level adjustment only when a collision of a certain intensity is to be expected. If the processing device has determined a probable collision and has located the point of impact, it will calculate an optimal vehicle height for the imminent collision, based on the data supplied by the detection device. The vehicle height is calculated such that the collision occurs in a region of a vehicle part with a particularly high passive safety. If the vehicle is to be secured all around, at least four detection devices are required for this purpose, specifically in the front and rear region as well as in the two side regions.
The signal emitted on the basis of the calculation by the processing device is conducted to actuators which carry out a vehicle level adjustment corresponding to the calculation.
In order to carry out a sufficiently rapid level change, it is advantageous to provide an energy accumulator from which the actuators can obtain energy. Preferably, for example, in the case of a side collision, a level change is endeavored in the range of 0.5 seconds; that is, at a level changing speed of 0.3 m per second. In this case, it is not necessary to move the entire vehicle to the calculated level. It is sufficient to correspondingly move only the vehicle side facing a possible collision.